Simple question,

   What does class Random require?
I tried this code:

r=Random.new(315)
printf("%d\n",r.rand(10))

and go this error:

test.rb:1: uninitialized constant Random (NameError)

spent some time looking in google and google groups but no luck.
It's a pretty simple problem, maybe somebody here can help me?
TIA
-Tom Z